Research by ComfyUI-PromptChain
Fixes for building custom nodes with dynamic input slots and custom editors in ComfyUI.
- Dynamic Input Slots - Reference code for nodes that spawn new input slots as you connect to them
- Ctrl+Z Fix - Stops ComfyUI from hijacking undo/redo when typing in CodeMirror or contentEditable
- Click Fix - Stops the node from being selected when you click inside a custom editor
If you're building a custom node with:
- Input slots that grow/shrink dynamically
- A code editor (CodeMirror, Monaco, Ace)
- Any contentEditable text box
...you'll hit these bugs. This extension fixes them and shows you how.
cd ComfyUI/custom_nodes
git clone https://github.com/mobcat40/ComfyUI-DynamicInputsHotFixRestart ComfyUI. Find the demo node under FrontendPatches category.
ComfyUI's ChangeTracker listens for Ctrl+Z/Y globally to trigger workflow undo/redo. It only skips native <input> and <textarea> elements, not contentEditable or CodeMirror editors. When you press Ctrl+Z in a contentEditable div, it deletes your node instead of undoing your text.
The fix adds a capture-phase keydown listener that runs before ChangeTracker. When Ctrl+Z/Y is pressed in an editable element, it calls stopImmediatePropagation() to prevent ChangeTracker from seeing the event. The editor then handles undo/redo natively.
This is cleaner than the old tagName spoof approach:
- No global prototype patching
- Only affects Ctrl+Z/Y keydown events
- Easy to understand and debug
When you click inside a custom editor, ComfyUI selects the node and highlights all connected wires. Annoying flicker.
The fix hooks onNodeSelected and immediately deselects using a triple-clear pattern (immediate + microtask + rAF) to catch all timing edge cases.
The demo node shows the pattern: start with one empty slot, add more as connections are made, clean up on disconnect. See web/main.js for the full implementation.
Key points:
- Use
onConnectionsChangehook slotType === 1for inputs"*"type accepts any connection- Always keep one empty slot at the end
Both patches can be toggled off in ComfyUI Settings. Useful for testing if ComfyUI fixed these upstream.
Tested on ComfyUI v0.9.2. The dynamic inputs work natively now (Vue reactivity was fixed upstream). The two patches are still required for custom editors.
MIT